Chemical mechanical polishing (CMP) is one process commonly used in the manufacture of high-density integrated circuits to planarize or polish a layer of material deposited on a substrate. The substrate may be provided to a polishing station on a polishing system and retained in a carrier head that controllably urges the substrate against a moving polishing pad. CMP is effectively employed by providing contact between a feature side of the substrate and moving the substrate relative to the polishing pad while in the presence of a polishing fluid. Material is removed from the feature side of the substrate that is in contact with the polishing surface through a combination of chemical and mechanical activity.
The carrier head typically includes a retaining ring that circumscribes the substrate and may facilitate holding of the substrate in the carrier head. One or more surfaces of the retaining ring are typically in contact with the polishing pad and with polishing materials during polishing. While the retaining ring is typically adapted to endure polishing of multiple substrates, the surfaces that are in contact with the polishing pad experience wear and periodic replacement of the retaining ring is necessary.
Therefore, there is a need for a method and apparatus that improves durability of the retaining ring in a polishing system.